.header{
    background: #eaebea;
    height: 70px;
    line-height: 70px;
    border-bottom: 2px solid #dedede;
    .grid{
        color: #fff;
        text-align: right;
        position: relative;
        a{
          font-size: 20px;
          color: #000;
          margin-left: 10em;
        }
        .logo{
            position: absolute;
            background: url(../img/logo.png) 0 center no-repeat;
            height: 72px;
            width: 150px;
            left: 0;
            margin: 0;
        }
    }
}
.app .header .grid a:nth-child(3){
    font-weight: bold;
}
.intro .header .grid a:nth-child(2){
    font-weight: bold;
}
.about .header .grid a:nth-child(4){
    font-weight: bold;
}